40 amp power supply ???

[rijo1]

Hi , I need to build a 40 amp power supply that has an input voltage
of 120 volts and an output voltage of 12 volts - 13.5 volts . The power
supply will be used for amateur radio so it needs to be quiet . The
transformer I want to use will come out of a battery charger . I need to
regualte the voltage to DC at the voltages I have specified .
I don't want to use a battery charger and a battery for a power
source .
If anyone has a good design and is willing to send me schematics on
it , please send it to me . Be sure to remove no in front of (
nemonet.com.)
Thanks , Rick

 

[Ban]

rijo1 wrote:

Hi , I need to build a 40 amp power supply that has an input voltage
of 120 volts and an output voltage of 12 volts - 13.5 volts . The
power supply will be used for amateur radio so it needs to be quiet .
The transformer I want to use will come out of a battery charger . I
need to regualte the voltage to DC at the voltages I have specified .
I don't want to use a battery charger and a battery for a power
source .
If anyone has a good design and is willing to send me schematics on
it , please send it to me . Be sure to remove no in front
of ( nemonet.com.)
Thanks , Rick

The transformers in chargers are usually unsuitable for this purpose. They
have a lot of interiour resistance and will also not give the advertized
current. Sorry
--
ciao Ban
Bordighera, Italy

 

[Rich Grise]

On Wed, 02 Feb 2005 04:11:01 +0000, rijo1 wrote:

Hi , I need to build a 40 amp power supply that has an input voltage
of 120 volts and an output voltage of 12 volts - 13.5 volts . The power
supply will be used for amateur radio so it needs to be quiet . The
transformer I want to use will come out of a battery charger . I need to
regualte the voltage to DC at the voltages I have specified .
I don't want to use a battery charger and a battery for a power
source .
If anyone has a good design and is willing to send me schematics on
it , please send it to me . Be sure to remove no in front of (
nemonet.com.)
Thanks , Rick

The battery itself in a charger/battery arrangement is part of the
regulation circuit. You could use a battery charger transformer if it's
ferroresonant, with very few changes. Typically, a ferroresonant charger
provides charging current to the battery until it reaches its float
voltage. The charger then sits there, (at float voltage, typically 14.6)
since a ferroresonant transformer inherently regulates voltage output and
limits its own output current.

So, get a 12V car taillight bulb, stick that across the output of your
charger, and run anything you want to off the charger output, because it
will very probably be somewhere between 12 V and 14.6 V, with an amount of
ripple, at 120 HZ, that's inversely proportional (roughly) to the current
drain of your load.

Have Fun!
Rich